linux-kernel - [PATCH 1/4] Add a lock that will be needed by the next patch

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Pine.LNX.4.64.1208311440350.2212@file.rdu.redhat.com>
Date:	Fri, 31 Aug 2012 14:41:15 -0400 (EDT)
From:	Mikulas Patocka <mpatocka@...hat.com>
To:	Eric Dumazet <eric.dumazet@...il.com>
cc:	Jens Axboe <axboe@...nel.dk>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Jan Kara <jack@...e.cz>, dm-devel@...hat.com,
	linux-kernel@...r.kernel.org, Jeff Moyer <jmoyer@...hat.com>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	kosaki.motohiro@...fujitsu.com, linux-fsdevel@...r.kernel.org,
	lwoodman@...hat.com, "Alasdair G. Kergon" <agk@...hat.com>
Subject: [PATCH 1/4] Add a lock that will be needed by the next patch

Add a lock that will be needed by the next patch.

I am submitting this as a separate patch, because the act of adding an
extra field to "struct block_device" affects performance significantly.

So that performance change from adding the lock field can be
differentiated from the performance change of locking.

Signed-off-by: Mikulas Patocka <mpatocka@...hat.com>

---
 drivers/char/raw.c |    2 -
 fs/block_dev.c     |   60 +++++++++++++++++++++++++++++++++++++++++++++++++++--
 include/linux/fs.h |    4 +++
 3 files changed, 63 insertions(+), 3 deletions(-)

Index: linux-3.5-rc6-devel/include/linux/fs.h
===================================================================
--- linux-3.5-rc6-devel.orig/include/linux/fs.h	2012-07-16 20:20:12.000000000 +0200
+++ linux-3.5-rc6-devel/include/linux/fs.h	2012-07-16 01:29:21.000000000 +0200
@@ -713,6 +713,8 @@ struct block_device {
 	int			bd_fsfreeze_count;
 	/* Mutex for freeze */
 	struct mutex		bd_fsfreeze_mutex;
+	/* A semaphore that prevents I/O while block size is being changed */
+	struct rw_semaphore	bd_block_size_semaphore;
 };
 
 /*

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/